COPENHAGEN, July 26 (Reuters) – Police in Denmark detained six environmental activists on Tuesday protesting the felling of trees in a forest to make room for a research centre for wind turbines.

Protesters said they were not opposed to the centre, but to the location.

The test centre is meant to further Denmark’s position as world leader in wind power, commonly seen as environmentally friendly renewable energy as it consumes no fossil fuels and produces no emissions.

The protest began 10 days ago at Thy in windy northwestern Jutland where Denmark’s wind industry aims to test giant turbines up to 250 metres high (820 feet).

“We are not against the centre, we are not against the wind industry — on the contrary,” Kent Klemmesen, chairman of the campaign against the project, told Reuters. “We are against the location, because we feel there are far better alternatives.”

Protesters argue that the effects of the huge windmills on human and animal life have not been studied adequately and the 1,200 hectares (2,965 acres) of forest should be preserved.

Though tree felling has begun, Amos Stenner, an activist who spent five hours up in a tree on Tuesday, said he was not giving up. “It is very possible, that I will go up a new tree tomorrow,” he told Reuters.

The test centre project is run by the Danish Technical University DTU, with support from industry, including wind turbine manufacturers Vestas and Siemens and state-owned DONG Energy.